/* 
 Calculate Circle Area using Java example
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class CalcCircleAreaExample {
    public static void main(String [] args) {
        int radius = 0;
        System.out.println("Please enter radius of a circle");

        try {
            // Get the radius from console
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            radius = Integer.parseInt(br.readLine());

        }
        catch (NumberFormatException ne) {
            System.out.println("Invalid radius value" + ne);
            System.exit(0);
        }

        catch (IOException ioe) {
            System.out.println("IO Error: " + ioe);
            System.exit(0);
        }
        double area = Math.PI * radius * radius;
        System.out.println("Area of a circle is " + area);
    }
}
